Similar quantities of mannans and SPs were reported previously in the related seaweed C. fragile (Suringar) Hariot. Overall, both seaweed cell walls comprise ∼40%–44% of their dry weights. Within the SP group, a variety of polysaccharide structures from pyruvylated

arabinogalactan sulfate and pyruvylated galactan sulfate to pyranosic arabinan sulfate are present in Codium cell walls. In this paper, the in situ distribution of the main cell-wall polymers in the green seaweed C. vermilara was studied, comparing their arrangements with those observed in cell walls from C. fragile. The utricle cell wall in C. vermilara showed by TEM a sandwich structure of two fibrillar-like layers of similar width delimiting a middle amorphous-like zone. By immuno- and chemical imaging, the in situ Selleckchem Y 27632 distribution of β-(14)-d-mannans and HRGP-like epitopes was shown to consist of two distinct cell-wall layers, whereas SPs are distributed Vemurafenib mw in the middle area of the wall. The overall cell-wall polymer arrangement of the SPs, HRGP-like epitopes, and mannans in the utricles of C. vermilara is different from the ubiquitous green algae C. fragile, in spite of both being phylogenetically very close. In addition, a preliminary cell-wall model of the utricle moiety is proposed for both seaweeds, C. fragile and

C. vermilara. “
“GTPases of the Ras superfamily regulate a wide variety of cellular processes including vesicular transport and various secretory pathways of the cell. ADP –

ribosylation factor (ARF) belongs to one of the five major families of the Ras superfamily and serves as an mafosfamide important component of vesicle formation and transport machinery of the cells. The binding of GTP to these Arfs and its subsequent hydrolysis, induces conformational changes in these proteins leading to their enzymatic activities. The dimeric form of Arf is associated with membrane pinch-off during vesicle formation. In this report, we have identified an arf gene from the unicellular green alga Chlamydomonas reinhardtii, CrArf, and showed that the oligomeric state of the protein in C. renhardtii is modulated by the cellular membrane environment of the organism. Protein cross-linking experiments showed that the purified recombinant CrArf has the ability to form a dimer. Both the 20-kDa monomeric and 40-kDa dimeric forms of CrArf were recognized from Chlamydomonas total cell lysate (CrTLC) and purified recombinant CrArf by the CrArf specific antibody. The membranous environment of the cell appeared to facilitate dimerization of the CrArf, as dimeric form was found exclusively associated with the membrane bound organelles. The subcellular localization studies in Chlamydomonas suggested that CrArf mainly localized in the cytosol and was mislocalized in vesicle transport machinery inhibitor treated cells.